A Case of Fungal Keratitis Caused by Purpureocillium lilacinum: A Microbiological Review of Korean Cases / 대한의진균학회지

ABSTRACT

Purpureocillium(P) lilacinum is a ubiquitous, saprophytic filamentous fungus that is infrequently reported in keratitis and cutaneous infections. However, the microbiological characterization of the culture isolates is limited in Korea. A 56-year-old male who suffered a pine needlestick to his right eye 10 days previously presented with ocular opacity and pain. A microscopic examination of a corneal scraping by Gram staining and calcofluor white staining was negative for bacteria and fungi. Fungal culture yielded pure white cottony molds on Sabouraud's dextrose agar after a 3-day incubation. Microscopic examination further revealed a mixture of a verticillate arrangement of phialides resembling the Penicillium structure and sparsely branched conidiophores bearing single to small clusters of conidia. This was initially presumed to be a species of Penicillium but the colonies never turned green with further incubation. It was subsequently identified as P. lilacinum by 28S rDNA sequencing and MALDI-TOF mass spectrometry. Antifungal susceptibility test revealed that this organism was resistant to flucytosine, amphotericin B, fluconazole, itraconazole, voriconazole, and caspofungin. After treatment with topical 5% voriconazole and oral itrazonazole combined with multiple debridements for 2 weeks, the patient was discharged with improved visual acuity. We thus report the first case of P. lilacinum infection that required molecular identification due to mixed conidiogenesis features and that showed laboratory-confirmed antifungal resistance in Korea.